High-voltage power distributor

ABSTRACT

A power distributor ( 200 ) with at least two incoming lines ( 101 - 103 ) and a method for manufacturing such a power distributor is suggested. Each incoming line comprises a conductor ( 106 , 107 ) and an individual screen ( 114 ). The conductors of the incoming lines are connected at a connection point (V 1 ,V 2 ), which is enclosed by a screen shield ( 201 ) that contacts each individual screen ( 114 ) of the incoming lines. The screen shield ( 201 ) is made from electrically conducting plastic material. Screen shields made from electrically conducting plastic material is easier to manufacture and less expensive than metal screen shields.

FIELD

The present disclosure firstly relates to a high-voltage powerdistributor comprising a screen shield to ensure electromagneticcompatibility of the power distributor. Secondly, the present disclosurerelates to a screen shield for such a power distributor. Furthermore,the present disclosure relates to a method for manufacturing ahigh-voltage power distributor.

BACKGROUND

In electric cars it is a requirement to distribute electric energy froma battery or a generator to consumers of this electric energy such as anelectric driving motor, actuators, heaters or cooling equipment just toname a few examples. To this end, it is necessary to provide forelectric connections between conductors of electric lines. In hybridcars and purely electric cars many times high-voltage systems areutilized with voltages in the range of 60 V-1500 V DC and 30 V-1000 VAC. For such high-voltage electric systems electric lines need a screento shield high electric fields. In high-voltage power distributorsdistributing electric power for example from the battery to severalelectric consumers conductors of different electrical lines or cablesare connected. In the interest of electromagnetic compatibility also theone or several connection points between the conductors of the differentelectrical lines need an effective screen.

Today the screen in conventional power distributors is made from metal,for instance copper, brass or steel or any other metal or alloy havingsufficient electric conductivity. However, manufacturing of metallicscreens is expensive.

In view of the mentioned limitations of existing power distributors,there remains a desire for a high-voltage power distributor that has asufficient electromagnetic compatibility that is less expensive tomanufacture.

SUMMARY

According to a first aspect the present disclosure suggests a powerdistributor with at least two incoming lines. Each line comprises aconductor and an individual screen. The conductors of the incoming linesare connected at a connection point, which is enclosed by a screenshield that contacts each individual screen of the incoming lines. Thescreen shield is made from electrically conducting plastic material.

A screen shield made from electrically conducting plastic material iseasier to manufacture and less expensive than the metal screen shield.It is noted that the incoming lines may be of a single core type with asingle conductor. But the incoming lines may also be of a multicore typewith several conductors. In this case only one single individual screenencloses the multiple conductors of the multicore line.

Advantageously, the screen shield comprises elastic springs contactscontacting the screens of the incoming lines. The elastic springcontacts facilitate making a good electrical contact to the screens ofthe incoming lines. At the same time the elastic spring contacts cancompensate for mechanical tolerances of the components making theelectrical contact.

It has been found useful to make the elastic spring contacts from metal.Most metals have good electrical conductivity and are mechanicallystable.

In the interest of a further improved electrical contact, the elasticspring contacts comprise one or several spring tongues. Each springtongue establishes a contact point which provides for a resilientelectrical contact. This can be particularly advantageous to make theelectrical contact resistant against vibrations.

In one embodiment the elastic springs are molded together with thescreen shield. According to this approach the elastic spring contactsare an integral part of the screen shield, which makes the screen shieldeven more efficient to manufacture.

In a particularly advantageous embodiment, the elastic spring contactsare molded together as in-mold parts with the screen shield. The springcontacts establish a metal-to-metal contact to the screen of theincoming lines. This metal-to-metal contact provides for a goodelectrical conductivity. At the same time, the electrical contactbetween the screen shield made from electrically conducting plasticmaterial to the metal spring contacts is better than just afriction-locked contact between metal and electrically conductingplastic material in the case when the spring contacts are also made fromelectrically conducting plastic material.

Advantageously, that the elastic spring contacts establish anelectrically conducting path connecting the elastic spring contacts witheach other. In this way the spring contacts contacting the screens ofthe lines provide for an electrically conducting path between thescreens. The electrically conducting path enables to transfer screencurrents from line screen to line screen of the lines.

In a practical embodiment the incoming lines comprise a plurality ofconductors, which are connected with other conductors of the otherincoming lines at a plurality of connection points.

In a further development the power distributor comprises an insulationbody which is arranged inside the screen shield. The insulation body isadapted to separate connection points between the conductors. Theinsulation body is a simple concept to assure mechanical and electricalreliability of the power distributor.

In this case it has been found useful to arrange spacer betweenconductors of different incoming lines fixing the connection points atpredefined positions inside the insulation body. The spacers cooperatewith the insulation body to fix the connection points in the insulatingbody.

In an advantageous further development, the power distributor comprisesa housing made of insulating plastic material enclosing the screenshield. The housing protects the power distributor from environmentalinfluences such as dirt, humidity, and mechanical stress.

According to a second aspect, the present disclosure suggests a screenshield molded from electrically conducting plastic material within-mould metallic spring contacts. This type of screen shield is easy tomanufacture and at the same time provides for good electrical contactbetween the screen shield and screens of incoming lines in a powerdistributor.

According to a third aspect, the present disclosure suggests a methodfor manufacturing a power distributor according to the first aspect ofthe present disclosure. The method comprises

-   removing an outer insulation jacket of incoming lines;-   removing an insulation form conductors of the incoming lines;-   electrically connecting the conductors of the incoming lines;-   lifting a screen from an inner insulating jacket to make room for an    under-crimp sleeve;-   crimping the under-crimp sleeve onto an insulating jacket;-   placing the screen back onto the under-crimp sleeve are fixed on the    insulating jacket, the screen is folded back onto the under-crimp    sleeve;-   placing the crimp sleeve on top of the screen and the under-crimp    sleeve;-   crimping the crimp sleeve;-   enclosing bare conductors in an insulating body;-   enclosing the insulating body in a screen shield according to second    aspect of the present disclosure.

In the development the method further comprises arranging anelectrically insulating housing around the screen shield.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present disclosure are illustrated in thedrawings and are explained in more detail in the following description.In the figures, the same or similar elements are referenced with thesame or similar reference signs. It shows:

FIG. 1 an exploded view of a conventional high-voltage powerdistributor;

FIG. 2 an exploded view of a high-voltage power distributor according tothe present disclosure;

FIG. 3 a lower half shell of the screen shield shown in FIG. 4 ;

FIG. 4 a screen shield made from electrically conducting plasticmaterial with integrated elastic springs; and

FIG. 5 a schematic flow diagram of a method for manufacturing ahigh-power distributor according to the present disclosure.

In the figures the same or similar components are labelled with the sameor similar reference signs.

DETAILED DESCRIPTION

FIG. 1 shows an exploded view of a conventional power distributor 100for connecting conductors of incoming lines 101-103. Each one of theincoming lines 101-103 comprises two conductors 106, 107 as it is shownin the insertion in FIG. 1 where the structure of line 101 is shown ingreater detail as a representative example for all lines 101-103. Theconductors 106, 107 are covered by an insulation 108 to form individuallines 111,112. The individual lines 111,112 are sheathed by an innerinsulating jacket 113. The insulating jacket 113 is surrounded by ascreen 114 made of a wire braid, for instance. In other embodiments thescreen 114 is made of stripes of thin metal foil that is wound in ahelical manner around the jacket 113. On top of the wire braid of thescreen 114 there is an outer insulation jacket 115. In the drawing,distances are shown between the individual components to improve theirdistinguishability. In reality such distances may not exist.

The conductors 106 of the incoming lines 101-103 are connected at aconnection point V1 by ultrasonic welding for instance. Likewise, theconductors 107 of the incoming lines 101-103 are connected at aconnection point V2. An insulation body 116 accommodates the connectionpoints V1, V2. Inside the insulation body 116 the connection points areseparated by a wall (not shown in FIG. 1 ) preventing direct contactbetween the connection points V1,V2. The power distributor 100 comprisesa screen shield 117 including a lower half shell 118 and an upper halfshell 119. All bare conductors or current carrying metallic parts areenclosed by the insulation body 116. Therefore, the electricallyconducting half shells 118, 119 can be placed on top of the insulationbody 116 to enclose the connection points V1, V2 and those portions ofthe conductors 106, 107 which are not covered by the screen 114 of theincoming lines 101-103. To avoid a gap between the screens 114 of theincoming lines 101-103 and the screen shield 117, the half shells 118,119 are provided with half circular extensions 121 forming circularenclosures for the screens 114 of the incoming lines 101-103 when thehalf shells 118, 119 are put together in their mounted position. Theextensions 121 make electrical contact to the screens 114. Properelectrical contact between the screen shield 117 and the screens 114 isachieved by means of under-crimp sleeves 122 and crimp sleeves 123. Theunder-crimp sleeves 122 are crimped onto the insulating jacket 113 ofthe incoming lines 101-103, with the screen 114 of the lines 101-103folded upwards by 90°. Then the half shells 118,119 are placed aroundthe connection points V1,V2. The screens 114 of the lines 101-103 arethen placed on the extensions 121 of the screen shield 117 andelectrically connected to the screen shield 117 with the crimp sleeves123. The crimp sleeves 123 also hold the half shells 118, 119 together.

Before joining the half shells 118,119, spacers 124 are arranged in thegaps between the individual lines 111, 112 of the incoming lines101-103. The spacers 124 hold the connection points V1, V2 in placeinside the insulation body 116. After the half shells 118, 119 areconnected by the crimp sleeves 123, the spacers 124 fix the connectionpoints V1, V2 in place inside the insulation body 116.

For protection against environmental influences such as dirt, humidityetc. the power distributor 100 comprises a housing 126 to enclose theelectrical parts of the power distributor 100. A sealing mat 127 tightlycloses an opening 128 of the housing 126. A stopper 129 cooperates withthe housing 126 to secure the correct positioning of the sealing mat 127in the opening 128 of the housing 126. A cover 131 closes the housingand is held in position by cooperating latching means provided on thehousing 126 and the cover 131, respectively.

FIG. 2 illustrates a high-voltage power distributor 200 according to thepresent disclosure. The power distributor 200 is structured very similarto the power distributor 100 shown in FIG. 1 . One important differencebetween both power distributors 100, 200 is that the power distributor200 comprises a screen shield 201 which is made from electricallyconducting plastic material. The screen shield 201 is made up of a lowerhalf shell 202 and an upper half shell 203. When the half shells 202,203 are combined to form the screen shield 201, the screen shield 201provides for three channels 204 (FIG. 4 ) for receiving the incominglines 101-103. Like in the high voltage distributor 100 described inconnection with FIG. 1 , the under-crimp sleeves 122 are crimped ontothe insulating jacket 113 of the incoming lines 101-103, with the screen114 of the lines 101-103 folded upwards by 90°. After the under-crimpsleeve 122 are fixed on the insulating jacket 113, the screen 114 isfolded back onto the under-crimp sleeve 122 and fixed by crimp sleeve123 which is placed on top of the screen 114 and the under-crimp sleeve122. The crimp sleeve 123 is crimped in this position and establishes anelectrical connection to the screen 114.

The mounting of the other components of the high voltage distributor 200is essentially the same as it has been described in connection with thehigh voltage distributor 100. Specifically, the conductors 106 of theincoming lines 101-103 are connected at a connection point V1 forinstance by ultrasonic welding. Likewise, the conductors 107 of theincoming lines 101-103 are connected at a connection point V2. Aninsulation body 116 accommodates the connection points V1, V2. Insidethe insulation body 116 the connection points are separated by a wall(not shown) preventing direct contact between the connection pointsV1,V2. The insulation body 116 encloses all bare conductors and currentcarrying metal parts. The spacers 124 hold the connection points V1, V2in place inside the insulation body 116 after the half shells 202, 203are connected. The half shells 202, 203 are provided with in-moldedelastic spring contacts 206, 207. The spring contacts 206, 207 makeelectrical contact to the crimp sleeves 123 and via the crimp sleeves123 to the screen 114 of each incoming line 101-103. The elastic springcontacts 206, 207 will be described in greater detail further below withreference to FIGS. 3 and 4 . The elastic spring contacts 206, 207 aremade from spring metal with good electric conductivity, e.g. in therange of 5×10⁶ - 60×10⁶ S/m.

For protection against environmental influences such as dirt, humidityetc. the power distributor 200 comprises a housing 126 to enclose theelectrical parts of the power distributor 200. A sealing mat 127 tightlycloses an opening 128 of the housing 126. A stopper 129 cooperates withthe housing 126 to secure the correct positioning of the sealing mat 127in the opening 128 of the housing 126. The stopper 129 is provided withprotrusions 130 a, 130 b, which are placed between the lines 101,102 and102,103, respectively, to separate the lines. A cover 131 closes thehousing and is held in position by cooperating latching means providedon the housing 126 and to the cover 131, respectively.

FIG. 3 shows the lower half shell 202 in greater detail including thein-molded elastic spring contacts 206. Each spring contact 206 includesfour cutout spring tongues 301 which are bent in a radial directiontowards an imaginary center of the half circular spring contact 206. Formounting the two half shells 202, 203 together, the lower half shell 202is provided with a ridge 302 and a groove 303 on the face to be joinedwith the upper half shell 203 that is provided with complementarystructures. The ridges 302 and grooves 303 facilitate the correctassembly of the half shells 202, 203 and diminish - or completelyclose - the gap between both half shells to improve the performance ofthe shielding effect against electromagnetic interference. The halfshells 202, 203 are furnished with cooperating latching means 304 thathold together the half shells 202, 203.

FIG. 4 illustrates the screen shield 201 when the half shells 202, 203are mounted together. The elastic spring elements 207 are in-moldedparts of the upper shell 203. Each spring element 207 is provided withfour cutout spring tongues 401 which are bent in a radial directiontowards an imaginary center of the half circular spring contact 207. Thespring contacts 206, 207 form a hollow cylinder with an inner diameterthat essentially corresponds to the outer diameter of the crimp sleeves123 except where the spring tongues 301, 401 are bent towards the centerof the hollow cylinder. When the crimp sleeves 123 of the lines 100-103are placed inside the spring contacts 206 of the lower half shell 202and the upper half shell is latched together with the lower half shell,then the spring tongues 301, 401 are bent radially outside to make roomfor the crimp sleeves 123. As a result, the spring tongues 301, 401exert an elastic force onto the crimp sleeves 123 and establish a goodfriction-locked electrical contact to the crimp sleeves 123. At the sametime, the in-mold spring contacts 206, 207 make good electrical contactto the half shells 202, 203 made from electrically conducting material.It has been found that this structure provides for better electricalcontacts and then compared to with a screen shield that contacts thescreens 114 of incoming lines 101-103 with elastic spring contacts whichare made from conducting plastic material.

The spring contacts 206, 207 contacting the screens 114 of the lines101-103 provide for an electrically conducting path between the screens114 of the lines 101-103. The electrically conducting path enables totransfer currents from line screen 114 to line screen 114 of the lines101-103. The metal spring contacts 206, 207 are better suited for thispurpose than contacts made from conductive plastic because of the lowercontact resistance. Typical requirements for contact resistance anddelta transfer impedance between screens can thus be met. The otherparts of the screen shield 201 only provides for a shielding effect andconsequently only must meet the requirements for shielding attenuation.The electrical conductivity of electrically conducting plastic issufficient for this purpose.

In other embodiments the spring contacts 206, 207 are provided withfewer or more spring tongues 301, 401.

In an alternative embodiment the metal spring contacts are replaced byspring contacts integrally molded with half shells which simplifies themanufacturing of the screen shield. Thus, instead of the metal springcontacts, the spring contacts are also made from electrically conductingplastic material. This alternative embodiment can be employed inapplications where the electrical contact provided by the plastic springcontact is found to be sufficient to satisfy reduced conductivityrequirements.

FIG. 5 shows a schematic flow diagram illustrating a method formanufacturing the power distributor 200. In a first step S1 the outerinsulation jacket 115 of the incoming lines 101-103 is removed. In stepS2 the insulation 108 from conductors 106, 107 is removed as well toprovide access to the bare metal of the conductors 106, 107. In step S3the conductors 106, 107 are connected at connection points V1, V2 forinstance by ultrasonic welding. However, other connection technologiescan be used as well, e.g. resistance welding, Laser welding, frictionstir welding, and plasma welding to name only a few. In step S4 thescreen 114 is lifted from the inner insulating 113 jacket to make roomfor an under-crimp sleeve 122. For instance, the screen can be foldedback by 90° allowing to put in the under-crimp sleeve directly on theinner insulating jacket 113. Then, the under-crimp sleeve 122 is crimpedin step S5 onto the insulating jacket 113. In step S6 the screen from114 is placed back onto the under-crimp sleeve 122. In step S7 the crimpsleeve 123 is put on top of the screen 114 and the under-crimp sleeve122 and then crimped in step S8. In step S9 all bare conductors and theconnection points V1, V2 are enclosed in the insulating body 116, whichsubsequently is enclosed in the screen shield 201 in step S10. Finally,in step S11 the electrically insulating housing 126 encloses the screenshield 201.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” does not exclude a plurality.

A single unit or device may perform the functions of multiple elementsrecited in the claims. The fact that individual functions and elementsare recited in different dependent claims does not mean that acombination of those functions and elements could not advantageously beused.

List of reference signs 100 Power distributor 302 ridge 101-103 Incominglines 303 Groove 106,107 Conductors 304 Latching means 108 Insulation111, 112 Individual lines 401 Spring tongue 113 Inner insulating jacket114 Screen 115 Outer insulation jacket 116 Insulation body 117 Screenshield 118 Lower half shell 119 Upper half shell 121 Half circularextension 122 under-crimp sleeve 123 Crimp sleeve 124 Spacer 126 Housing127 Sealing mat 128 Opening 129 Stopper 130 a,b Protrusion 131 Cover 201Screen shield 202 Lower half shell 203 Upper half shell 206,207 Springcontact 301 Spring tongue

1. A power distributor comprising: at least two incoming lines, whereineach line comprises a conductor and an individual screen, wherein theconductors of the incoming lines are connected at a connection point,which is enclosed by a screen shield that contacts each individualscreen of the incoming lines, and wherein the screen shield is made fromelectrically conducting plastic material.
 2. The power distributoraccording to claim 1, wherein the screen shield comprises elastic springcontacts contacting the screens of the incoming lines.
 3. The powerdistributor according to claim 1, wherein the elastic spring contactsare made from metal.
 4. The power distributor according to claim 2,wherein the elastic springs contacts comprise one or several springtongues.
 5. The power distributor according to claim 1, wherein theelastic springs contacts are molded together with the screen shield. 6.The power distributor according to claim 1, wherein the elastic springscontacts are molded together as in-mold parts with the screen shield. 7.The power distributor according to claim 1, wherein that the elasticspring contacts establish an electrically conducting path electricallyconnecting the elastic spring contacts with each other.
 8. The powerdistributor according to claim 1, wherein the lines comprise a pluralityof conductors, which are connected with other conductors of the otherincoming lines at a plurality of connection points.
 9. The powerdistributor according to claim 1, wherein the power distributorcomprises an insulation body which is arranged inside the screen shield,and that the insulation body is adapted to separate connection pointsbetween the conductors.
 10. The power distributor according to claim 9,wherein spacers are arranged between conductors of different incominglines fixing the connection points at predefined positions inside theinsulation body.
 11. The power distributor according to claim 1, whereinthe power distributor comprises a housing made of insulating plasticmaterial enclosing the screen shield.
 12. A screen shield molded fromelectrically conducting plastic material comprising in-mould metallicspring contacts.
 13. A method for manufacturing a power distributoraccording to claim 1, comprising removing an outer insulation jacket ofincoming lines; removing an insulation form conductors of the incominglines; electrically connecting the conductors of the incoming lines;lifting a screen from an inner insulating jacket to make room for anunder-crimp sleeve; crimping the under-crimp sleeve onto the innerinsulating jacket; placing the screen back onto the under-crimp sleeve;placing the crimp sleeve on top of the screen and the under-crimpsleeve; crimping the crimp sleeve; enclosing bare conductors in aninsulating body; enclosing the insulating body in a screen shield moldedfrom electrically conducting plastic material comprising in-mouldmetallic spring contacts.
 14. The method according to claim 13, furthercomprising arranging an electrically insulating housing around thescreen shield.